N-Nitrosobis(2-oxopropyl)amine (BOP) methylates hamster liver and pancreas DNA in vivo and also alkylates liver DNA with a longer chain electrophile of unknown nature. We are seeking to explain these qualitative and quantitative differences in alkylation using in vitro systems of metabolism and alkylation. A detailed study of the kinetics and the products of BOP metabolism by microsomal preparations from hamster colon, liver and pancreas will indicate the mechanism of BOP activation to a methylating electrophile. The metabolic products to be measured are CO2, alcohols, aldehydes (trapped as phenylhydrazones) and nitrosamines. The products of the in vitro alkylation of DNA by 3H-BOP will be examined by HPLC analysis of the hydrolysates. Metabolism and alkylation will also be studied using N-nitrosomethyl-(2-oxopropyl)amine (MOP) and N-nitrosomethyl(2-hydroxypropyl)amine (MHP), postulated proximate carcinogenic forms of BOP. Further, the reaction of N-nitroso-2-oxopropyl-carbamate will be studied. These products will be a source of alkylated bases and nucleosides to be used as marker compounds. These reactions will also simulate the decomposition of alpha hydroxy nitrosamines containing the 2-oxopropyl moiety. A variety of chemical syntheses are proposed to obtain other marker bases and nucleosides, essential for a complete understanding of the mechanism of DNA alkylation by BOP.